"Rosan" fittings for connecting fluid lines which are available from Rexnord, Specialty Fastener Division, are well-known and are illustrated in FIG. 1. Essentially, a threaded adapter is threadably secured in the boss of a case or housing where fluid egresses or ingresses. A tube nut secures the connecting tube at its ferrule. As noted, a hole is drilled through the side wall of the nut and is adapted to receive the lock wire. The other end of the lock wire is typically secured to the housing by a hole formed directly in the wall of the case or housing. The threaded adapter is prevented from rotating by a lock ring which has a spline on its inner diameter engaging a complementary spline formed on the outer diameter of the threaded adapter. Splines are preformed in an enlarged recess formed on the front end of the passageway in the boss of the case or housing. The splines are either formed by a broaching tool or by electrical discharge milling process (EDM). The lock ring carries splines complementing the splines in the recess which serves to prevent the fitting from rotating. Obviously, from the foregoing, it is apparent that the lock ring and lock wire are antirotation mechanisms that prevent the fitting from dislodging. In some installations, the lock wire is optional.
However, for safety purposes lock wire is often used, notwithstanding the fact that industry would rather do without. While locating the lock wire hole in the housing itself has been acceptable in some applications, in others it is not. The hole in the housing obviously weakens the structure to some degree and in certain applications the housing cannot accommodate a lock wire hole.
We have found that we can obviate the problem noted above by providing a serrated ring adapted to engage the outer spline of the lock ring which has an upper flange or indent that has a lock wire hole adapted to receive the lock wire passing through the hole in the nut. The upper flange extends radially inwardly and is nested in a reduced diameter on the adapter between the inner end of the tube nut and a shoulder formed on the adapter adjacent the recess.